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Presentation of the NosoSim platform

NosoSim is an agent-based platform which simulates pathogen transmission in a geographically realistic hospital ward. Human agents such as patients and health-care workers circulate in the ward; their actions are reproduced at all times.

The hospital ward in NosoSim

Geographical description

The hospital ward is composed of corridors, patient rooms and staff rooms, among which human agents may move. Any geographical combination of these elements may be entered into NosoSim and used for simulations.

Health-care
workers (HCWs)

A given number of patients (or
patient rooms) are assigned to each HCW.

All HCWs
have a profile, which determines their daily timetable,
and the duration and nature (in terms of time spent in direct contact) of their
patient visits. For each HCW profile present in the ward, the HCW to patient
ratio is entered as a parameter.

Examples of HCW profiles in a 18-bed ICU :

Profile

Presence in the ward

No. of assigned patients

No. of visits per patient

Duration of patient visits

Portion of visits spent in direct contact

Day nurse

7AM-7PM

2

3

25 minutes

60%

Physician

9AM-6PM

6

1

25 minutes

40%

Therapist

9AM-6PM

18

1

15 minutes

40%

Patients

Patients do not move
from the room they are allocated, except for entering or leaving the ward.
Rooms are supposed to be single. The bed occupancy may be fixed in simulations.

Pathogen
circulation in NosoSim

One or
several pathogens may circulate in the ward.

For each
simulation, users may either select circulating pathogens from a built-in
library, or define a new pathogen. For each pathogen, the duration of
colonization is entered, as well as the transmissibility and the duration of
natural immunity following decolonization.

Colonization
of patients and HCWs

NosoSim
simulated human colonization with these pathogens, rather than infection.

Patients are
colonized until they are detected and isolated, or effective antibiotics are prescribed
to them, or they leave the ward. A temporary immune period follows their decolonization.

HCWs may
only be transiently colonized for a short duration, which is provided for each pathogen.
No immune period follows the end of transient colonization.

Transmission
of colonization

Colonization
is transmitted from a patient to another via the hands of HCWs. During all
patient-HCW contacts, there is a chance of colonization transmission; the
transmission probability per minute of contact depends on the involved pathogen
as well as on the profile of the HCW. However, the probability of patient-to-HCW
transmission is the same as that of